There are many applications in which it is desirable to bolt together securely the ends of skeletal framework members extending in various directions. In one application with respect to which the invention will be particularly described a domed modular skeletal framework of tubular members may be assembled to form a space enclosure to which a covering such as flexible fabric, plastic sheeting, or rigid panels may be secured, for example to form an automobile garage, a utility building, a swimming pool enclosure or any of various other such enclosures. The skeletal framework may consist of a plurality of straight-segmented arches arranged in spaced, parallel vertical planes, with each such arch connected to one or more others by a series of spacer members, or purlins, which are parallel to each other and perpendicular to the planes of the arches, as well as by a series of diagonal braces extending in other directions. At some positions in the framework it may only be required to join a pair of arch-members to each other and to one other arch-connecting member, while at other points it may be necessary also to join one or more additional arch-connecting members extending at an angle to the plane of the arches.
There are a variety of junction devices which might be used to join together the ends of such tubular members. However, many of these are relatively complex and expensive to manufacture and/or difficult to assemble or disassemble, and in many cases they require either many different kinds of parts for use at different locations in the framework, or require an elaborate multi-purpose junction whose cost and complexity is wasted when only two or possibly three tube ends are to be joined, rather than four or more.
Accordingly, it is an object of my invention to provide a new and useful skeletal framework using a novel junction for securing together the adjacent ends of framework members.
Another object is to provide such junction which is capable of securing together the adjacent ends not only of a pair of coplanar framework members, but also to secure one or more additional framework members which extend at an angle to the plane of the coplanar pair of framework members.
A further object is to provide such a junction which uses only very simple, easily assembled parts which are simple and inexpensive to manufacture, and which parts may be used interchangeably at a large number of junctions in the assembly and assembled and disassembled using only a simple wrench.